"Consolidated sediments" is essentially solid rock made from materials that have been metamorphosed or cemented together. For example, limestone is made of oceanic deposits of billions of shells; likewise, sandstone is made of tiny grains of sand. Ground water flows through fracture networks and/or pore space in these consolidated sediments....

Most of the water and additives used in hydraulic fracturing (or “fracking”) remain deep underground in the geologic formation from which the oil or gas is being extracted. But some of the fluid, mixed with water or brine from the formation, returns through the well to the surface and is referred to as “produced water”. After a well is brought on-...

A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep. Faults may range in length from a few millimeters to thousands of kilometers. Most faults produce repeated...

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